[CALCITE-4745] RelDataTypeSystemImpl.deriveAvgAggType typing error

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Not A Bug
• Affects Version/s: 1.27.0
• Fix Version/s: 1.27.0
• Component/s: core
• Assignee: Unassigned
• Reporter: keaton drebes
• Created: 17/Aug/21 20:54
• Updated: 18/Aug/21 12:56
• Resolved: 18/Aug/21 12:56

Description

Currently, RelDataTypeSystemImpl.deriveAvgAggType returns the type of the input argument to the aggregation.

This is obviously incorrect, AVG(A) where A has values [0, 1] should return .5, which is not an integer. This issue effects all SqlAggFunction's, since they ultimately use deriveAvgAggType for type inference. 

PR here: https://github.com/apache/calcite/pull/2498